U.S. patent number 3,974,527 [Application Number 05/523,794] was granted by the patent office on 1976-08-17 for artificial hip-joint for arthroplasty.
Invention is credited to Yakov Isaevich Shersher.
United States Patent |
3,974,527 |
Shersher |
August 17, 1976 |
Artificial hip-joint for arthroplasty
Abstract
An artificial hip-joint for arthroplasty comprising a first
endoprosthesis of the acetabulum of a patient, coupled to a second
endoprosthesis of the proximal portion of the femur rigidly
connected by way of a neck with a pin insertable into the medullary
canal of the femur. The first endoprosthesis is formed as a seat
whereof the exterior surface is adapted to be impacted in the
acetabulum, while the interior surface of the seat is spherical
with a cavity of which the height being greater than the radius but
smaller than its diameter. The head of the second endoprosthesis is
of a spherical configuration and is provided with a centrally
located opening; on the side thereof there is provided a
cylindrical section disposed along the axis of the opening;
eccentrically with respect to the center of the sphere.
Inventors: |
Shersher; Yakov Isaevich
(Saratov, SU) |
Family
ID: |
20566799 |
Appl.
No.: |
05/523,794 |
Filed: |
November 14, 1974 |
Foreign Application Priority Data
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Nov 19, 1973 [SU] |
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1967205 |
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Current U.S.
Class: |
623/22.15 |
Current CPC
Class: |
A61F
2/32 (20130101); A61F 2/3662 (20130101); A61F
2002/30879 (20130101); A61F 2002/3401 (20130101); A61F
2002/368 (20130101); A61F 2002/365 (20130101); A61F
2002/30845 (20130101); A61F 2002/3621 (20130101) |
Current International
Class: |
A61F
2/32 (20060101); A61F 2/30 (20060101); A61F
2/34 (20060101); A61F 2/36 (20060101); A61F
001/24 () |
Field of
Search: |
;3/1.91-1.913,1
;128/92C,92CA |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Frinks; Ronald L.
Attorney, Agent or Firm: Haseltine, Lake & Waters
Claims
What is claimed is:
1. An artificial hip-joint for arthroplasty, such for the
replacement of the affected actabulum and the head of the femur of
a patient, comprising a first endoprosthesis of the acetabulum,
formed as a seat having an exterior surface and an interior
surface; said exterior surface being defined by blades with
sharpened edges and apertures through which growing bony tissue may
protrude; said blades being arranged in circular rows that are in
turn arranged in axially disposed tiers, one above the other; said
interior surface of the seat having the shape of a sphere with a
cavity that has a height greater than its radius but smaller than
its diameter; a second endoprosthesis of the proximal portion of
the femur, coupled with said seat and including a spherical head, a
neck and a pin; said head has a radius corresponding to that of
first endoprosthesis, for location of said head therein; the latter
including a blind, substantially central opening for receiving said
neck made in a body portion of said sphere; the exterior spherical
surface of said head at the side of said opening having a
cylindrical portion of a radius smaller than that of said sphere,
to allow for the introduction of the head into said first
endoprosthesis; said cylindrical portion being such that, at the
introduction of said neck into said opening, it is positioned along
the axis of said opening, eccentrically of said spherical head;
said opening having an open end located at the side of said
cylindrical portion; said pin being connected by one end through
said neck with said spherical head, and being adapted to be
introduced with its other end into the intraosseal canal of the
femur.
2. The artificial hip joint as defined in claim 1, wherein said
opening made in said body portion of the sphere is located in a
midportion of said cylindrical portion.
Description
The present invention relates to artificial joints for
intra-articular prosthetic replacement and, more particularly, to
artificial hip-joints for arthroplasty.
It is directed to assist in regaining hip-joint mobility lost in
Bekhterev's disease, arthritis deformans, arthritis infectiosa,
aceptic necrosis of the femoral head, as well as femoral neck
fracture in the aged.
It is known in the art to employ an artificial hip-joint (USSR
Inventor's Certificate No. 278,022 of Jan. 28, 1966) which
comprises an endoprosthesis of the acetabulum hinged to an
endoprosthesis of the proximal portion of the femur, with a
spherical head rigidly fitted over a neck extending into an
intraosseal pin.
The endoprosthesis of the acetabulum is formed as a seat whereof
the exterior surface is formed as a plurality of tiered blades with
sharpened edges, which blades are provided with apertures
wherethrough burgeoning bony tissue may advance.
The interior surface of the seat of the acetabulum endoprosthesis
has an irregularly shaped through opening composed of a cylindrical
portion and a conical portion designed to receive two split inserts
enveloping more than half of the sphere of the head of the
endoprosthesis of the proximal portion of the femur. The
endoprosthesis of the proximal portion of the femur is attached to
the endoprosthesis of the acetabulum by riveting the split inserts
onto the exterior surface of the endoprosthesis of the
acetabulum.
The above-described known artificial hip-joint has some serious
disadvantages stemming from the fact that it incorporates two
inserts.
First of all, the processes of manufacturing the two inserts and
machining the irregularly shaped recess formed in the acetabulum
endoprosthesis seat are highly labor consuming.
Secondly, the riveting of the inserts causes the latter to be
deformed.
Thirdly, the inserts cause the head of the endoprosthesis of the
proximal portion of the femur to be reduced in size, thereby
limiting the mobility of the joint.
Fourthly, with the endoprosthesis head reduced in size, the
specific pressure per unit area of the sphere rises, adding to the
wear of the joint surfaces.
It is an object of the present invention to eliminate the foregoing
disadvantages.
A further object of the present invention is to provide an
artificial hip-joint that is easy to manufacture.
Still another object of the present invention is to provide an
artificial hip-joint affording a larger angle of joint
movement.
Yet another object of the present invention is to provide an
artificial hip-joint allowing the specific intraarticular pressure
per unit area to be reduced.
These and other objects are attained by the inventive artificial
hip-joint for arthroplasty which comprises an endoprosthesis of the
acetabulum formed as a seat, whereof the exterior surface is formed
as a plurality of tiered blades with sharpened edges, which blades
are provided with apertures wherethrough burgeoning bony tissue may
advance, and an endoprosthesis of the proximal portion of the
femur, coupled with said seat. The latter endoprosthesis
incorporates a spherical head with a centrally located opening to
receive a neck whereby the head is linked with a pin introduced
into the medullary canal of the femur. The interior surface of the
first-mentioned endoprosthesis is made spherical, the height of the
cavity of said sphere being greater than the radius but smaller
than the diameter, and the head of the second-named endoprosthesis
has a cylindrical section disposed on the side of the opening,
which cylindrical section is disposed along the axis of the
opening, eccentrically with respect to the centre of the sphere of
the endoprosthesis head.
Besides, the opening in the head designed to receive the neck is
disposed in the midportion of the cylindrical section.
Such a hip-joint structure is easy to manufacture, prevents sphere
deformation, increases the angle of movement of the hinge joint,
and reduces the specific intra-articular pressure per unit surface
area. The proposed artificial hip-joint is sturdier, more reliable
and has a longer service life than the prior art artificial
hip-joints of the same type.
After a prosthetic replacement operation with the use of the
proposed artificial hip-joint, the patients have a greater freedom
of movement of the joint than in the case of the prior art
artificial hip-joint built around two inserts.
The present invention will be further understood from the following
detailed description of a preferred, exemplary embodiment thereof
taken in conjunction with the accompanying drawings, wherein:
FIG. 1 is a general view, partially cut away, of an exemplary
artificial hip-joint according to the invention;
FIG. 2 illustrates hinging of the hip-joint as assembled;
FIG. 3 is a longitudinal section of an endoprosthesis of the
acetabulum shown in side elevation;
FIG. 4 is a view taken along the arrow A in FIG. 3;
FIG. 5 is a side elevation of the head of an endoprosthesis of the
proximal portion of the femur; and
FIG. 6 is a longitudinal section of the head of an endoprosthesis
of the proximal portion of the femur.
Referring now to the drawings, the proposed artificial hip-joint
for arthroplasty comprises an endoprosthesis 1 (FIG. 1) of the
acetabulum and an endoprosthesis 2 of the proximal portion of the
femur, the endoprostheses 1 and 2 being hinged one to the other.
The endoprosthesis 2 of the proximal portion of the femur comprises
a spherical head 3, a neck 4 and a pin 5 to be introduced into the
femoral medullary canal.
The endoprosthesis 1 of the acetabulum (FIGS. 2, 3 and 4) is formed
as a seat whereof the exterior surface is formed as a plurality of
blades arranged in tiers. The edges of blades 6 are sharpened to
ensure failsafe implantation into the acetabulum walls. The blades
6 are provided with apertures 7 wherethrough burgeoning bony tissue
may advance.
Interior surface 8 (FIGS. 3 and 4) of the endoprosthesis 1 of the
acetabulum is spherical, the height of the cavity of the sphere
being greater than the radius but smaller than the diameter for
holding the head 3 of the endoprosthesis 2 of the proximal portion
of the femur.
The head 3 (FIGS. 5 and 6) of the endoprosthesis 2 of the proximal
portion of the femur is spherical in configuration and is provided
with a centrally located opening 9 for receiving the neck 4. On the
side of the opening 9 the head 3 has a cylindrical section 10
disposed along the axis of the opening 9, eccentrically with
respect to the centre of the sphere of the head 3.
When putting the artificial hip-joint together, the head 3 is
fitted into the endoprosthesis 1 of the acetabulum in such a way
that the cylindrical section 10 registers with the entrance to the
recess of the spherical interior surface 8. Then the head 3 is
turned through 180.degree..When fitting the head 3 over the neck 4,
the former has to be so positioned that the cylindrical section 10
is disposed on the sides with respect to the neck 4.
The foregoing hip-joint for arthroplasty ensures ease in
manufacture, high reliability of the hinge joint, considerable
mobility, and a long service life.
* * * * *